Both other two GPUs use the Cape Verde core. While the 7800M is a fully enabled 640 core part, the 7700M disables some couple compute clusters and ends up with 512 cores and 32 texture units. AMD also clocks the 7700M lower.

AMD Radeon HD 7900M, 7800M, and 7700M

Radeon HD 7900M

Radeon HD 7800M

Radeon HD 7700M

Stream Processors

1280

640

512

Texture Units

80

40

32

ROPs

32

16

16

Z/Stencil

128

64

64

L2 Cache

512KB

512KB

512KB

Core Clock

850MHz

800MHz

675MHz

Memory Clock

4.8GHz

4.0GHz

4.0GHz

Memory Type

2GB GDDR5

2GB GDDR5

2GB GDDR5

Memory Bus Width

256-bit

128-bit

128-bit

Memory Bandwidth

153.6GB/s

64GB/s

64GB/s

PCI Express

3.0

3.0

2.1

Other features include AMD's ZeroCore technology along
with AMD Enduro Technology. AMD ZeroCore technology powers the GPU down to a virtually zero-watt state when the GPU switches to inactive mode. The Enduro Technology automatically switches between integrated graphics and the AMD Radeon(TM) discrete GPU, depending on system or application requirements -- helping to maximize battery life. That means that idle power draw should be a step down compared to previous mobile GPUs, and for CrossFire configurations it means that the secondary GPU can be completely shut down when it's not in use. Enduro works like dynamic switchable graphics on the previous generation 6000M parts.

The new GPUs will be launched by several notebook vendors
starting from today.